docs: add advanced skills for Vitest, Pinia, and Vue built-ins

Add comprehensive reference documentation for:
- Vitest: environments, projects/workspaces, type testing, vi utilities
- Pinia: HMR, Nuxt integration, SSR setup
- Vue: built-in components (Transition, Teleport, Suspense, KeepAlive) and advanced directives

.agents/skills/vueuse-functions/references/usePreferredReducedMotion.md

@@ -0,0 +1,42 @@
+---
+category: Browser
+---
+
+# usePreferredReducedMotion
+
+Reactive [prefers-reduced-motion](https://developer.mozilla.org/en-US/docs/Web/CSS/@media/prefers-reduced-motion) media query.
+
+## Usage
+
+```ts
+import { usePreferredReducedMotion } from '@vueuse/core'
+
+const preferredMotion = usePreferredReducedMotion()
+```
+
+## Component Usage
+
+```vue
+<template>
+  <UsePreferredReducedMotion v-slot="{ motion }">
+    Preferred Reduced Motion: {{ motion }}
+  </UsePreferredReducedMotion>
+</template>
+```
+
+## Type Declarations
+
+```ts
+export type ReducedMotionType = "reduce" | "no-preference"
+/**
+ * Reactive prefers-reduced-motion media query.
+ *
+ * @see https://vueuse.org/usePreferredReducedMotion
+ * @param [options]
+ *
+ * @__NO_SIDE_EFFECTS__
+ */
+export declare function usePreferredReducedMotion(
+  options?: ConfigurableWindow,
+): ComputedRef<ReducedMotionType>
+```